en passant

/ɒn pæˈsɑːnt; French ɑ̃ pasɑ̃/

adverb

1.

in passing: in chess, said of capturing a pawn that has made an initial move of two squares to its fourth rank, bypassing the square where an enemy pawn on its own fifth rank could capture it. The capture is made as if the captured pawn had moved one square instead of two